Substitute for lithographic stones and method of making same.



No. 773,368. PATENTED OCT. 25, 1904. G. BOWER & F. W. GAUNTLETT. SUBSTITUTE FOR LITHOGRAPHIO STONES AND METHOD OF MAKING SAME.

APPLICATION FILEDTEB. 23, 1904.

N0 MODEL.

UNITED STATES Patented October 25, 1904.

PATENT OFFICE.

GEORGE BO'WER, OF ST. NEOTS, AND FREDERICK 'WVILLIAM GAUNTLETT, OF LONDON, ENGLAND:

SUBSTITUTE FOR LITHOGRAPHIC STONES AND METHOD OF MAKING SAME.

SPECIFICATION forming part of Letters Patent No. 773,368, dated October 25, 1904. Application filed February 23, 1904:. Serial No. 194.87% (No model.)

To all whom, it may concern.-

Be it known that we, GEORGE BOWER, residing at The Shrubbery, St. Neots, Hunts, and FREDERICK TVILLIAM GAUNTLETT, residing at 2 Tower Royal, Oannon street, London, England, subjects of the King of Great Britain, have invented certain new and useful Improvements in Substitutes for Lithographic Stones and Methods of, Making the Same, of

To which the following is a specification.

The object of this invention is to provide substitutes for the stones which are commonly used for lithographic purposes and which have surfaces equal to or superior to those of the 5 stones and at the same time have the flexibility of the sheets of metal which have also been used for the same purpose and which are especially suitable both for fiat-bed and rotary machines. In order to accomplish this, we

take metallic sheets and either convert the surfaces of such sheets into an oxid of the same metal or else we form an oxid of another metal upon the said metallic sheets, orwe may form both oxids at the same time, if desired,

5 or, again, we may convert the surface of the metallic sheet into an oxid and over this form oxids of two or more metals. In any case the oxid or oxids are made to form tenacious coatings to the metallic sheets, and such oxids by 3 their nature take the lithographic ink readily and are sufliciently absorbent and flexible as to stand bending round the smallest cylinders which are used or likely to be used in printing-machines.

By one method we take sheets of iron or steel and convert the surfaces thereof into an oxid or combination of oxidsof iron by the action of heat and steam which may be advantageouslysuperheated or by the action of 4 the heat and air or products of combustion, or in any of the ways in which iron or steel may be oxidized so as to form a firm adherent coating of oxid to the metal itself. Preferably we so oxidize the iron or steel that it may have a light French gray .color and be more or less of the nature of the magnetic oxid of iron, which is also a preservative against the formation of the red oxid or common rust, and therefore of especial value. This coating of oxid is flexible to a considerable degree, and so does 5 not separate from the iron or steel sheets when they are bent, and, moreover, for lithographic and printing purposes the surfaces presented by such oxids are equal or superior to those of the best stones. Or we may form an oxid or oxids of one or more other metals upon the metallic sheets by chemical means with the application of heat. As an example, iron or steel may be dipped into a cupric salt, such as the sulfate or nitrate of copper, when if the sheets of iron or steel be clean an even layer of metallic copper is formed upon them, which by the application of heat in an oxidizing atmosphere may be converted into an oxid of copper of the desired color, texture, and 5 tenacity, or the copper or other metals may be deposited by the aid of electricity upon such other metallic sheets as may be desirable and likewise converted into the porous and tenacious oxids which are desired. Or, yet 7 again, the second metal, or it may be combination of metals, may be deposited upon the primary metallic sheets by the simple method of dipping, as is done in the manufacture of galvanized iron or steel or of tin plates. In the case where iron or steel sheets are coated with zinc or zinc and tin combined and then the whole oxidized by heat in an oxidizing atmosphere of any convenient nature the result is metallic iron or steel in the interior of the sheet, oxid of iron on each side of this and closely adhering thereto, and externally films of the oxids of zinc or tin, or both, and firmly adherent to the oxid of iron. The oxids of zinc and tin are white in colora 5 point of considerable importance and value; but almost any suitable color may be produced by the use of different oxids. v

Russian sheet-iron is simply a case where iron or steel sheets are partly oxidized in the 9 process of manufacture and in no way evades the true spirit of our invention, which generally consists in the employment of metallic sheets and in the conversion of the surface of such sheets to an oxid or combination of oxids, which provides the necessary porosity and surface texture for lithographic-printing purposes, or otherwise coating the metallic sheets primarily used with some other convenient the sheets (1 instead of the magnetic oxid.

oxid or oxids of the required porosity and texture, it being understood that the original sheets may also have their surfaces oxidized at the same time, if desired. In this manner we combine the advantages of the stones and the metallic sheets which have hitherto been em iloyed and at the same time we eliminate the disadvantages which are common to either class of material by itself, for the oxid or combination of oxids, however produced, supplies the necessary surface and the metallic portion of the prepared sheet the required flexibility, and in order to show how our invention may be carried into effect we annex a sheet of drawings herewith, illustrating one method of producing the magnetic oxid and which has been in successful operation.

In the drawings, (1 Z) is a retort or muflie surrounded by brickwork c 0. A gas-pipe (Z supplies a series of burners (2, which play upon the bottom of the retort c b. The products of combustion escape through openings at f. A lid is provided for the retort, and this is perforated with small holes.

71. is a steanrpipe froma boiler, while Z: is a smaller pipe fitted with a funnel into which oil is allowed to drop, so that the oil ultimately mixes with the steam entering at it. Themixtu re then flows through the downright pipe 122, which is heated, so that the oil becomes vaporized, and the steam and oil-vapor then pass along 21 to the longitudinal pipe 0, which runs the whole length of the retort and is perforated with small holes at its lower portion, so that the oil-vapor and the steam are compelled to strike upon the heated bottom of the retort/z l). The object of this is to insure that any free oxygen which may be with the steam shall be compelled to combine with the hydrocarbon vapor. After such combination the mixture passes through a mass of iron turnings or borings, as shown at p, and which are at a fairly high temperature. The steam now deprived of any free oxygen, which it almost always has as ordinarily produced, passes upward through the sheets (1 of iron or steel, which are suspended in the retort or muflle (t 7/, and by the decomposition of the steam the surfaces of the sheets are converted into magnetic oxid. The final exit of the different gases or vapors is through the holes in the lid 0 of the retort a, Z).

The object of the oil is to prevent any possibility of the red oxid being formed upon A hydrocarlcion vapor or combustible gas may be used instead of oil to eliminate the free oxygen; but oil is convenient and does its work well. The borings or turnings at 11 cause the steam to move upward evenly among the suspended sheets in the muifle, and this action is further aided by the perforations in the lid q.

The proper quantities of steam and oil which should pass over a given quantity of plates can only be determined by experiment; but when they are once properly proportioned the plates after two or three hours exposure at a scarcely visible red heat will be found to be coated with a firm adherent film of magnetic oxid.

We have shown gas-burners for heating the retort; but of course solid fuel may be used, if convenient.

Sheets of iron or steel prepared as hereinbefore stated may be used for printing in precisely the same manner as lithographic stones are at present.

By the above methods we are enabled to produce plates having analogous surfaces to stones via, a surface which absorbs and re tains grease and water. The want of this is the great drawback to zinc and aluminium and the cause from which most of the trouble incidental to their working arises.

\Vhat we claim, and desire to secure by Letters Patent, is

1. A method of iminufacturing a substitute for lithographic stones which consists in forming a metallic plate with a coating of oxid of I metal to form a printing-surface by the subjecting of said plate in an oxidizing atmosphere to the application of heat.

2. As a new article of manufacture, a substitute for lithographic stones, consisting of a metallic plate having a printing-surface of oxid of iron.

3. As a new article of manufacture, a substitute for lithographic stones, consisting of a metallic plate having a firmly adhering coating of oxid of iron forming a printing-surface.

In testimony whereof we have hereunto set our hands in presence of two subscribing witnesses.

GEORGE BOWER. lfllllDilltlCK WILLIAM GAUNTLETT. \Vitnesses:

WM, 0. BROWN, FRED C. SMITH. 

